During which process do homologous chromosomes exchange parts to generate new allele combinations?

During which process do homologous chromosomes exchange parts to generate new allele combinations?

• A. Crossing over
• B. Recombination
• C. Zygote
• D. Nondisjunction error

Answer: (B)

The main concept is how genetic material is shuffled during meiosis to create new allele combinations. During prophase I of meiosis, homologous chromosomes pair up and non-sister chromatids exchange corresponding segments. This physical swap, called crossing over, produces recombinant chromatids that carry mixtures of parental alleles on the same chromosome, increasing genetic diversity in gametes. While recombination is the broader idea of generating new allele combinations in general, the specific act of exchanging chromosome parts is crossing over. The other options don’t describe this exchange process—one refers to fertilization and the other to an error in chromosome separation.

The main concept is how genetic material is shuffled during meiosis to create new allele combinations. During prophase I of meiosis, homologous chromosomes pair up and non-sister chromatids exchange corresponding segments. This physical swap, called crossing over, produces recombinant chromatids that carry mixtures of parental alleles on the same chromosome, increasing genetic diversity in gametes. While recombination is the broader idea of generating new allele combinations in general, the specific act of exchanging chromosome parts is crossing over. The other options don’t describe this exchange process—one refers to fertilization and the other to an error in chromosome separation.